And the “house divided” speech? Obviously, keeping the Union together was, by far, the primary aim of the war. But to pretend that slavery had little/nothing to do with the war is simply disingenous, and ignores the very reasons that keeping the Union together was even necessary.
I do not dispute that Lincoln was very much against slavery. I do not doubt that he would have done anything of which he could think to interfere with it and oppose it. I just dispute that the Union reasons for fighting the war had anything to do with it. Up till January of 1863, the continuance of slavery was an acceptable condition for a peace settlement. Leaving the Union was not.
Throughout the conflict, the one non negotiable was the exercise of that right expressed in the Declaration of Independence; The Right to leave. That was the one sticking point of the war.
See my post #72. Lincoln's big strategic mistake was turning a war that was about preserving the Union (which most in the North and many in the South thought was a worthy cause) into a war that was, rightly or not, perceived as being fought "to free the slaves." Many more people were willing to fight and die to preserve the union than to liberate slaves, and rightly so.